The present disclosure relates to plating deposition processes and equipment, and more particularly, to a method and masking assembly for selectively depositing a plating on a turbine airfoil while preventing deposition of the plating on a dovetail of the airfoil.
Gas turbine engines, such as those that power modern commercial and military aircraft, generally include a compressor section to pressurize an airflow, a combustor section to burn hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases.
Turbine section blades typically include an airfoil which extends into the hot core gases which result from the combustion of fuel in the upstream combustor section. Because of the high temperatures and corrosive effects of such gases on the airfoil s, standard practice may include application of a protective plating that provide insulation from the high temperatures and corrosive effects.
A root opposite the airfoil attaches the blade to a rotor disk of the engine and is not in need of protection from the high temperatures and corrosive effects of the hot core gases. The root often has a fir-tree shape that is assembled into a corresponding slot in a rotor disk such that after a prolonged time period, the root may exhibit a fatigue-related phenomenon referred to as fretting. Fretting has been found to be exacerbated by plating. Thus, in order to achieve the desired properties in the various s of the turbine airfoil to maximize service life only the airfoil is plated.
One method to plate only the airfoil is to segregate the airfoil with a mask that protects the root and platform underside before insertion into the plating solution. An operator manually inserts the airfoil into a mask. Installation may be relatively difficult and time consuming as the operator usually requires two hands and a wood table as leverage to wiggle the airfoil into the mask. As a gas turbine engine may contain upwards of eighty airfoils in one stage and multiple different stages, masking turbine components may be time consuming and expensive.